The present invention relates to the use of certain fructans, preferably certain inulins, for the manufacture of a composition for the prevention and/or treatment of colon cancer in non-bovine mammals.
The present invention also relates to the use of compositions comprising certain fructans, preferably certain inulins, for the prevention and/or treatment of colon cancer in non-bovine mammals, and to a method of prevention and/or treatment of colon cancer in non-bovine mammals.
Cancer in mammals is a disease which is already known from Ancient Times. Nowadays cancer, particularly lung, breast and colon cancer, has become one of the major causes of death of non-bovine mammals, in particular of humans, in the industrialised world.
The cancer disease is known to proceed in several steps, including genesis of cells of modified genome and functionality resulting in the formation of malignant cells; uncontrolled local proliferation of the malignant cells and invasion of adjacent normal body structures; and metastasis. During metastasis malignant cells are spread in a body cavity and/or throughout the body via the blood stream and/or the lymph, with invasion of various normal body structures. The invasion of the normal body structures results in their malfunctioning and/or destruction, eventually leading to the death of the affected mammal.
Various factors which can provoke carcinogenesis and cancer have already been identified, including certain viral infections, exposure to ionising radiation, exposure to certain mineral fibres, exposure to chemical mutagens, and improper diet.
As a result thereof various preventive measures have been introduced which have shown to be successful in preventing or reducing the occurrence of certain cancers.
Furthermore, various surgical and chemotherapeutical methods have been developed for the treatment of cancer. According to the type of cancer, the stage of the disease and the particulars of the affected mammal, these methods have been shown effective to a more or lesser degree.
Many reliable animal models for the study of the genesis and evolution of various cancers are available at present, enabling the evaluation of the preventive and curative properties of miscellaneous chemicals and dietary products.
Epidemiological studies in combination with studies on animal models have lead to the identification of dietary fibres as an important factor in the prevention and inhibition of certain cancers in mammals.
Dietary fibres are commonly defined as components of plant cells which are resistant to hydrolysis by the alimentary enzymes of man. Dietary fibres comprise cellulose, hemicellulose, polysaccharides, pectin, gums, waxes and lignin. According to this definition, fructans, which are soluble and edible polysaccharides, are dietary fibres. Fructans are composed of chains of carbohydrates which consist mostly of fructose units and in which fructosyl-fructose linkages constitute the majority of the linkages. Fructans commonly occur as polydisperse carbohydrates. They occur in plants, but they also can originate from bacterial activity and they can be synthesised enzymatically as well. All these fructans present typical dietary fibre properties; they are embraced by the present invention and are referred to herein as fructan(s).
Fructans are well known compounds including levan and inulin carbohydrates. Levans are D-fructans generally consisting of chains of fructose units which are essentially connected to each other by xcex2(2-6) linkages. Inulins are also D-fructans generally consisting of chains of fructose units but which are essentially connected to each other by xcex2(2-1) linkages. Most of the inulin chains terminate in one glucose unit.
Levans may occur as linear chain carbohydrates but they are mostly composed of branched fructose chains, whereas inulins are generally composed of linear chain carbohydrates but they may also occur as chains of fructose units which are branched to a larger or lesser extent. Levans and inulins which are suitable according to the present invention include linear and branched chain carbohydrates, as well as mixtures of said linear and branched chain carbohydrates.
Inulins occur in many plants and crops and can occur at concentrations of about 10 to 20% on fresh weight in chicory, dahlia tubers and Jerusalem artichoke. They can be isolated from these plants, purified, and optionally refined to remove impurities and undesired fractions of carbohydrates, at industrial scale, according to well known techniques.
Inulins can be represented by the general formulae GFn and Fm wherein G represents a glucose unit, F represents a fructose unit, n represents the number of fructose units linked to the terminal glucose unit, and m represents the number of fructose units linked to each other in the carbohydrate chain. The number of saccharide units (fructose and glucose units) in one fructan molecule, i.e. the values n+1 and m in the above formulae, are commonly referred to as the degree of polymerisation and represented as (DP). Often the parameter average degree of polymerisation ({overscore (DP)}) is used too, which is the value corresponding to the total number of saccharide units divided by the total number of saccharide molecules present in a given (poly)saccharide composition.
Inulin from plant origin is a polydisperse composition of fructose chains with a degree of polymerisation (DP) ranging from 2 to about 100, whereas inulin from bacterial origin usually has a higher degree of polymerisation.
Fructans, including inulins of general formulae GFn and Fm, with a lower degree of polymerisation, usually defined as a (DP) less than 10, are commonly named oligofructoses and are referred to herein accordingly.
Inulin is commercially available. For example, inulin from chicory is available as RAFTILINE(copyright) from ORAFTI, (Tienen, Belgium), in various grades. Typical RAFTILINE(copyright) grades are, for example , ST, ST-Gel and GR (which have an average degree of polymerisation ({overscore (DP)}) of 10 and contain in total about 8% by weight glucose, fructose and sucrose), LS (which has also an average degree of polymerisation of 10 but which contains in total less than 1% by weight glucose, fructose and sucrose), and HP (high performance inulin) and HP-Gel (which have an average degree of polymerisation of xe2x89xa723, commonly about 25, and are essentially free of glucose, fructose and sucrose).
Oligofructoses are usually obtained by partial, acidic or enzymatic hydrolysis of inulins and can also be obtained by enzymatic synthesis from sucrose , according to techniques which are well-known in the art. Oligofructoses are commercially available. Several grades of oligofructose are, for example, available from ORAFTI, (Tienen, Belgium), as RAFTILOSE(copyright), e.g. RAFTILOSE(copyright) P95 which contains about 95% by weight oligofructoses with a degree of polymerisation ranging from 2 to 7 and about 5% by weight in total of glucose, fructose and sucrose.
Dietary fibres, in particular fructans, are known to have effects on various physiological functions and mechanisms in mammals.
In non-bovine mammals, these fibres are almost not metabolised in the mouth, the stomach and the small intestine, and they thus almost quantitatively enter the large intestine where they are completely fermented by the colonic microflora. This phenomenon results in various beneficial health effects in non-bovine mammals such as, for example, a reduction of the intestinal transit time, a decrease of the intestinal pH, a bifidus stimulating activity in the colon, an increase of the stool weight (bulking) and stool frequency.
Fructans, particularly inulin, are also known to have a beneficial effect on lipid metabolism , including a lowering effect on blood cholesterol and on serum triglycerides, and an increasing effect on the HDL/LDL ratio.
P. D. Cooper et al., Molecul. Immunol., 23 (8), 895, (1986), describe the activation of the alternative pathway of complement by gamma-inulin (a specific polymorphic form of dahlia inulin), and it is known that an activator of the alternative pathway of complement can have a potential non-specific anti-tumour effect.
Furthermore, fructans, particularly inulin, are described to have potential in the prevention and inhibition of cancer.
P. D. Cooper et al., (Molecul. Immunol., 23 (8), 903, (1986) have demonstrated that intraperitoneally injected gamma-inulin can prolong the survival of melanoma bearing mice.
It has also been disclosed that cultures of bifidobacteria inhibit 2-amino-3-methyl-imidazol[4,5-f]quinoline induced colon, liver, and mammary carcinogenesis (B. S. Reddy et al., Cancer Res., 53, 3914-3918, (1993) and azoxymethane-induced colon carcinogenesis (N. Kulkarni et al., Proc. Soc. Exptl. Biol. Med., 207, 278-283, (1994) in rats.
European patent application EP 0 692 252 A1 discloses the suppressing effect of the oligofructose RAFTILOSE(copyright) P95 (ex ORAFTI, Belgium; consisting of 95% of oligofructose chains with a degree of polymerisation (DP) between 2 and 7) and of the inulins RAFTILINE(copyright) ST, GR and LS, (defined hereinbefore and having an average degree of polymerisation of about 10) on breast carcinogenesis induced by injection of N-methylnitrosourea (MNU) in rats as well as on the growth of the transplantable TLT tumour (Taper Liver Tumour) in mice. The investigated oligofructose and inulins showed to have about equal carcinogenesis protective and cancer inhibiting effects.
Furthermore, the relation between the intake of dietary fibres and the reduction of the risk of colon cancer has been disclosed in several publications, e.g. J. Potter et al., Principles of Chemoprevention, IARC Scientific Publication N 139, 61-90, (1996); G. R. Howe et al., J. Natl. Cancer Inst., 84, 1887-1896, (1992); and B. S. Reddy et al., Gastoenterol., 102, 1475-1482, (1992).
However, in spite of the enormous efforts already made in the fight against cancer diseases, and colon cancer in particular, the prevention and successful inhibition and curing of colon cancer is not always possible yet. Therefore; Medicine is still looking for improving the prevention, inhibition and curing of colon cancer. For various reasons such as the patient""s comfort, chemotherapeutical methods are most preferred. Accordingly, there is a continuously ongoing search for improved and/or alternative compositions and therapeutical methods presenting a beneficial effect with respect to the inhibition and/or treatment of colon cancer, and/or presenting less undesirable side effects compared to known compositions and therapeutical methods.
The applicant is providing by the present invention a solution to one or more of the above mentioned problems, which even may present additional advantages.
By the term colon cancer is meant herein the colon cancer disease in any of its steps, including colon carcinogenesis, the formation of malignant cells in the colon, proliferation of said malignant cells and formation of tumours in the colon and/or invasion of normal colon structures by said malignant cells.
The invention is based on the findings made by the inventors during extensive studies that fructans with a higher degree of polymerisation, in particular fructans having an average degree of polymerisation of 15 or higher, present improved preventive and inhibiting properties against colon cancer in non-bovine mammals compared to fructans with a lower degree of polymerisation.
In view of the prior art, it could be expected that fructans with a higher degree of polymerisation, could, as do certain fructans with a lower degree of polymerisation, have preventive and/or inhibitive properties against colon cancer. However, the surprising findings of the inventors that fructans, in particular inulins, with a higher average degree of polymerisation, present significantly enhanced preventive and inhibiting properties against colon cancer in non-bovine mammals, compared to fructans with a lower average degree of polymerisation, could not be expected at all having regard to the state of the art.
Accordingly, in one aspect, the present invention relates to the use of a fructan with an average degree of polymerisation of at least 15 for the manufacture of a composition for the prevention and/or treatment of colon cancer in non-bovine mammals, particularly in human beings.
In another aspect, the invention relates to the use of a composition comprising a fructan with an average degree of polymerisation of at least 15, for the prevention and/or treatment of colon cancer in non-bovine mammals, particularly human beings.
In a further aspect, the invention relates to a method for the prevention and/or treatment of colon cancer in non-bovine mammals, particularly human beings, by administering to said mammal susceptible of colon cancer, in need of such prevention or treatment, a composition comprising an effective dose of a fructan with an average degree of polymerisation of at least 15.
In one preferred embodiment, the fructan is levan, preferably with an average degree of polymerisation of at least 20, more preferably ranging from 20 to 50.
In another preferred embodiment, the fructan is inulin, preferably with an average degree of polymerisation of at least 20, even more preferably ranging from 20 to 70. In a further preferred embodiment, the inulin has an average degree of polymerisation ranging from 20 to 40. A typically preferred inulin has an average degree of polymerisation about 25.
Inulin essentially consisting of linear polysaccharide chains or inulin containing up to about 2% by weight branched polysaccharide chains, are suitable according to the invention, but inulin containing a higher percentage of branched chains and even inulin essentially consisting of branched polysaccharide chains, and even mixtures of said linear and branched inulins, are suitable as well according to the invention. Typical inulins suitable according to the present invention are chicory inulins, for example RAFTILINE(copyright) HP and RAFTILINE(copyright) HP-Gel (both high performance inulins [in short HP inulin] ex ORAFTI, Belgium), with an average degree of polymerisation of about 25.
By the term composition according to the present invention is meant herein a medicament, (i.e. a composition which has a prophylactic and/or a curative effect on a mammal to which it has been administered), as well as a functional food, (i.e. a food product for human beings or for a non-human mammal, containing an additional functional ingredient, and which apart from its nutritional properties, additionally provides to that being one or more beneficial physiological effects). In the functional food compositions according to the present invention, said additional functional ingredient is meant to be a fructan, including levans and inulins, as defined herein before. Typical beneficial physiological effects are, for example, beneficial effects on the digestive tract, effects on lipid metabolism and preventive effects against cancer, in particular colon cancer.
When, in accordance with the present invention, the composition is a medicament, it can consist of the defined fructan or it can comprise said fructan in combination with any pharmaceutically acceptable carrier, and optionally also in combination with one or more physiologically active compounds, drugs or prodrugs. Said medicament can have any form known in the art, and can be administered according to known methods. Preferably, the medicament is in the form of a powder, a tablet, a soft gel capsule, a syrup, a solution or a suspension, and is administered orally. However, when present in an appropriate galenic form, the composition can also be administered parenterally, via tube feeding or rectally.
When the composition according to the present invention is a functional food, it is orally administered and it can be present in any known food form, such as, for example, a table spread, a dairy product such as e.g. a milk, a dairy dessert, a yoghurt, or a cheese, an alcoholic or non-alcoholic drink, a bakery product, a chocolate, an ice cream, a meat product, a fruit preparation, a confectionery product, a cereal product, a sauce, a soup, a snack, a dry mix, a meal replacer, a pet food, and the like.
The daily dosis effective in providing prevention against colon cancer preferably ranges, depending from the mammal species and the fructan species, from 0.01 to 2 g/kg body weight, more preferably from 0.05 to 0.5 g/kg body weight.
The daily dosis effective in providing an inhibitive and/or curing effect on colon cancer preferably ranges, depending from the mammal species, the fructan species and the stage of development of the colon cancer, from 0.2 to 3 g/kg body weight, more preferably from 0.5 to 1.5 g/kg body weight.
In the method of prevention and/or treatment, including inhibition and/or curing, of colon cancer in non-bovine mammals, preferably human beings, the daily dose of the composition according to the present invention described hereinbefore, can be administered to a said mammal susceptible of colon cancer and in need for such treatment, according to known methods in one or more unit doses during a shorter or longer period of time, in function of strength of the effect provided by the composition. When the composition is a functional food and a preventive effect is aimed at, the functional food is advantageously administered in one or more forms over a longer period of time, most preferably during the whole lifetime of the mammal.
Besides the improved physiological, prophylactic and/or therapeutical effects of the fructans with a higher degree of polymerisation compared to fructans with a lower degree of polymerisation, the compositions and method of treatment according to the present invention present significantly additional advantages. The compositions, for example, are easy to take in or to administer, and the method of treatment is easy to apply, without significant discomfort for the concerned mammal. Furthermore, the presence of fructan chains with a higher degree of polymerisation reduces certain discomforts often encountered with the intake of non-digestible carbohydrates such as e.g. soft stools, diarrhea, flatulence, bloating and intestinal cramps. A further considerable advantage presented by the fructans, in particular the preferred chicory inulin, relating to the present invention, is that they are naturally occurring, biodegradable products which are deprived of toxic effects and that they can be taken in and administered to newborn as well as adult, including pregnant, and aged mammals. Compared to many known chemotherapeutical compositions, the intake of, administration of, and the treatment with a composition comprising the above defined fructans according to the present invention, is usually very well supported by the mammal and does not provoke significant undesirable side effects or a significant discomfort, if any at all, to the mammal. Furthermore, the fructans suitable according to the present invention are largely commercially available at acceptable cost.